Heat treating apparatus



July 27, 1965 WAYNE ETAL 3,197,601

HEAT TREATING APPARATUS Filed Jan. 26, 1962 3 Sheets-Sheet 1 July 27, 1965 Filed Jan. 26, 1962 F1E.E

l. R. WAYNE ETAL HEAT TREATING APPARATUS 3 Sheets-Sheet 2 July 27, 1965 R. WAYNE ETAL HEAT TREATING APPARATUS Filed Jan. 26, 1962 3 Sheets-Sheet 3 IN OUT WATER United States Patent 3,197,601 HEAT TREATING APPARATUS Ignatius R. Wayne, Chicago, Joseph W. ll'oliard, Villa Paris, and Howard K. Absler, Skoirie, IlL, assignors, by direct and mesne assignments, to Uarco, Incorporated, a corporation of Iilinois Filed Jan. 26, 1962, er. No. 169,036

4 Ciaims. (Ci. 21910.55)

This invention relates to heat treating apparatus and more specifically to an apparatus for heat treating collated continuous business forms with radio frequency energy.

Collated business forms generally comprise two or more strips of paper having interleaved strips of carbon paper held together by fastening means. Usually there is printing on more than one of the strips which must be maintained in registry by the fastening means.

In the manufacture of the particular forms described herein, the printed strips are properly assembled with the carbon strips, and a line of glue is applied to fasten the assembly together. Usually the glue is applied along one side or margin of the forms so that at a subsequent time the strips or individual form lengths may be separated.

To obtain a continuous high speed manufacturing operation it is desirable to provide some means for drying the glue after application more rapidly than obtainable by ordinary air drying. Before or after the drying process one or more lines of weakening are usually cut in the forms, and as a last step the forms are zig-Zag folded. it is important that the adhesive used to be in a condition to prevent shifting of one strip relative to one another during such subsequent operations.

The use of radio frequency energy for drying purposes has been attempted in various manufacturing processes. A particular problem is presented in the effective use of such energy in the manufacture of business forms due to the location and extent of the glue line that should be dried in the least possible time Without subjecting either the stationery or the carbon transfer coating on the interleaved strips to any deleterious effects. Passing collated strips of forms through a heating device in the usual Way would dry but a small portion of the adhesive present because the glue line which usually extends along one side of the collated form would be subjected to only a portion of the radio frequency energy. Hence, the forms must be passed through the heating apparatus at a speed slow enough to accomplish the heating and drying since only a portion of the available energy is used. However, it has been difficult to increase the speed of the drying process by previously known techniques and the production of collated forms has been limited.

it is therefore an object of this invention to provide an improved radio frequency heating apparatus for collated business forms.

A further object of this invention is to provide an apparatus for radio frequency heating and drying of collated business forms which subjects the forms to a series of points of radio frequency energy.

it is still a further object of this invention to provide a radio frequency heating apparatus having increased speed and efficiency for drying of collated business forms.

Another object of this invention is to provide in an apparatus for heat treating material, including a source of microwave, an energy absorbing member and a feeding device for moving the material; an energy transfer device. The energy transfer device comprises a chamber coupled to the microwave energy source and to the absorbing member for transferring energy to the absorbing member in a predetermined manner having a plurality of spaced points of maximum electrostatic intensity along approximately the longitudinal axis of the chamber. There is further provided means included in the chamber for receiving the material from the feed device and guiding the material through a plurality of the points of maximum intensity for periodically heating the material.

it is a further object of this invention to provide a heat treating apparatus wherein the material to be heat treated is passed longitudinally along a wave guide.

Another object of this invention is to provide a wave guide for heat treating collated business forms having a slot therein extending longitudinally along a wave guide substantially parallel to the longitudinal axis thereof.

It is still a further object of this invention to provide a wave guide for heat treating collated business forms having a longitudinal slot therein parallel to the axis of the wave guide provided with a radio frequency energy shield.

A further feature of the invention is to provide the apparatus for heat treating material wherein an electrostatic field is established in a wave guide having points of maximum intensity spaced therein and passing the material through successive ones of said points of maximum intensity for absorbing energy when in said points of maximum intensity and for cooling the material between said points of maximum intensity.

The features of the present invention which are believed to be novel, are set forth with particularity in the appended claims. The organization and manner of operation of the invention, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings, in the several figures of which like reference numerals identified like elements and in which:

FIGURE 1 is a plan View of the radio frequency heating apparatus;

FIGURE 2 is atop view of the apparatus of FIGURE 1;

FIGURE 3 is an end view of the apparatus in FIG- URE 1;

FIGURE 4 is a in FIGURE 1; and

FEGURE 5 is a section view along lines 5-5 in FIG- URE 4.

Referring now to FIGURE 1 which shows the heating apparatus from one side with the side panel removed, a frame member 11 is provided for supporting the various elements of the heating apparatus which generally consists of a magnetron assembly 12, a series of wave guide sections 13, 14, 1'5, 16, 17, 18 and 19 and a load device 21 In operation the magnetron .12 generates a high frequency radio signal which is propagated along the wave guide sections to the load 26 which is provided for absorbing unused energy of the wave and preventing a reflected wave from existing in the wave guide.

The power to the apparatus is supplied through cables 21 to a capacitor 22, a choke 23 and by connections (not shown) to a transformer 24. Power is coupled from this circuit to a pair of magnets 25, 26 of magnetron assembly 12 to provide the necessary power for actuation of a magnetron tube 27 shown in dashed lines.

Water is supplied through a water inlet 28, a solenoid controlled valve 29, and hoses 30, 31 and 32 to provide a circulating stream of water to cool magnetron 27 and provide the means for conducting away the heat from the load device 20.

In addition there is provided a support frame 33 and a support base 34 supporting the magnetron assembly 12 partial sectional view along lines 4-4 FIGURE 2, a top view of the heating apparatus of FIGURE 1, shows the frame member 11 supporting wave guide sections 13, 14, 15 16 and 17. A table 34 is mounted on frame 11 substantially parallel to the base of the apparatus and three slots 35, 36 and 37 are cut 23 therein. A paper guide 33 is secured to the table 34 through bolts 39, 40 and 41. A radio frequency shield is provided which is located on either side of a slot cut in wave guide 15 as hereinafter shown which consists of the table 34 and a member 42.

A portion of collated business forms 43 is shown traveling along the table 34 and has one edge shown being heat treated in the wave guide 15. It is to be understood that feed and take-up devices (not shown) provide for the travel of collated business forms 43.

FIGURE 3, an end view of the apparatus shown in FIGURE 1, shows the wave guide sections 16, 17 and support member 33 supporting the table 34. A slot 44 cut in wave guide section 16 allows paper 43 to travel along the wave guide section 15 and through section 16. (Means for allowing the paper to travel through section 15 are more clearly shown in FIGURES 4 and 5.) One edge of the paper 43 is shown spaced from a spacer element 45 which is mounted on the inner face of one wall of the wave guide section 15 as more clearly shown in FIGURES 4 and 5.

FIGURE 4 shows the detailed construction of wave guide sections 15, 16 and 17. Fastening means 46 and 47 in the form of bolts are shown for connecting the three sections of wave guides in electrical contact and in rigid mechanical abutment. The slot 44 in wave guide section 16 allows the collated forms 43 to enter this section of wave guide. In addition, a slot 48 is cut in wave guide section 15 which is adapted to receive the collated forms. Spacer 45 is shown with a tapered end 49 which provides for impedance matching of wave guide sections.

The form 43 is shown as including a longitudinally extending line of weakening 50, an adjacent glue line 51 anda series of feed holes 52. The line of weakening may, however, be added at a later time. It is to be noted that the glue line 51 is substantially centrally located in wave guide section 15.

FIGURE shows the forms 43 in wave guide section 15. In addition, section 17 is shown and the table 34 which both supports the forms 43 and provides the radio frequency energy shield along with element 42. Experience has shown that practically no loss occurs through the open slot because of the shield provided.

In operation of the embodiment shown the magnetron 27 supplies the high frequency energy signal which is propagated along the wave guide sections to the load 20. Sections 183 and 19 of the wave guide are provided for impedance matching. The wave establishes a series of points of maximum electrostatic intensity along wave guide section which are spaced substantially uniformly along the wave guide section and which have points of maximum intensity along line of travel of forms 43, and the glue line 51. Thus, the glue line is periodically subjected to electrostatic fields of high intensity with intermediate periods of low intensity. The frequency of oscillations of the magnetron is selected to obtain the greatest number of points of maximum electrostatic intensity along the wave guide commensurate with efiicient operation of the heating device.

In one embodiment of the invention it was found that with a wave guide section 15 approximately five feet long, the rate of travel of the collated forms therethrough was approximately 300 feet per minute with successful drying of the glue line 51.

While a particular embodiment of the invention has been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects, and, therefore, the aim in the appended claims is to cover all such changes and modifications as followed in the true spirit and scope of the invention.

We claim:

1. Apparatus for heat treating only a narrow longi- O tudinal band of a length of material, comprising:

a microwave energy source;

chamber means having an input connected with said source and establishing an elongated zone of high intensity electric field, said chamber means including a section of wave guide having a slot-like opening therein, said elongated zone of intensity electric field being established adjacent said slot and inside said wave guide;

means supporting said length of material in a plane extending through said zone and for travel in a di- .rection generally parallel with said zone, only said narrow longitudinal band of material being located in said zone, said band traveling through substantially the entire extent of said zone, other portions of the material traveling substantially outside said zone, the narrow longitudinal band being located along an edge of said length of material, said edge traveling through said wave guide.

2. The apparatus of claim 1 wherein said slotted section of wave guide is connected with said source through an elbow, said length of material traveling in a straight line to enter the wave guide.

3. The apparatus of claim 1 wherein said slot has a configuration establishing a high impedance at the frequency of said microwave energy source, confining the electromagnetic energy.

4. The apparatus of claim 1 wherein a strip of dielectric 7 material extends longitudinally inside said wave guide generally parallel with said slot.

References Cited by the Examiner UNITED STATES PATENTS RICHARD M. WOOD, Primary Examiner.

NORMAN YUDKOFF, Examiner. 

1. APPARATUS FOR HEAT TREATING ONLY A NARROW LONGITUDINAL BAND OF A LENGTH OF MATERIAL, COMPRISING: A MICROWAVE ENERGY SOURCE; CHAMBER MEANS HAVING AN INPUT CONNECTED WITH SAID SOURCE AND ESTABLISHING AN ELONGATED ZONE OF HIGH INTENSITY ELECTRIC FIELD, SAID CHAMBER MEANS INCLUDING A SECTION OF WAVE GUIDE HAVING A SLOT-LIKE OPENING THEREIN, SAID ELONGATED ZONE OF INTENSITY ELECTRIC FIELD BEING ESTABLISHED ADJACENT SAID SLOT AND INSIDE SAID WAVE GUIDE; MEANS SUPPORTING SAID LENGTH OF MATERIAL IN A PLANE EXTENDING THROUGH SAID ZONE AND FOR TRAVEL IN A DIRECTION GENERALLY PARALLEL WITH SAID ZONE, ONLY SAID NARROW LONGITUDINAL BAND OF MATERIAL BEING LOCATED IN SAID ZONE, SAID BAND TRAVELING THROUGH SUBSTANTIALLY THE ENTIRE EXTENT OF SAID ZONE, OTHER PORTIONS OF THE MATERIAL TRAVELING SUBSTANTIALLY OUTSIDE SAID ZONE, THE NARROW LONGITUDINAL BAND BEING LOCATED ALONG AN EDGE OF SAID LENGTH OF MATERIAL, SAID EDGE TRAVELING THROUGH SAID WAVE GUIDE. 